If an input signal is supplied to an amplifier, the input signal is amplified, and is output. If the output signal and input signal are denoted as y and x respectively, y is represented as a1·x. However, during the amplification by the amplifier, a distortion occurs, and is added to the output signal y. This distortion is nonlinear, and can be represented as a2·x2+a3·x3+a4·x4+ . . . . A measurement of this nonlinear distortion has been conventionally practiced (refer to Japanese Laid-Open Patent Publication (Kokai) No. H11-118873), for example. This nonlinear distortion is observed not only in amplifies but also in general electronic devices.
However, even if the nonlinear distortion is measured, it is not easy to determine how to compensate the nonlinear distortion.
It is an object of the present invention to compensate the nonlinear distortion based upon a characteristic relating to a characteristic of a device under test.